The present invention relates to telemetry for detecting the condition of pipelines, and more particularly to pipeline scanners.
A major problem in the pipeline industry is the maintenance of existing pipelines and particularly the early detection of corrosion, leaks, delamination, and rupture. Left undetected, such conditions typically result in substantial losses due to impaired pipeline carrying capacity, contamination of the product, and actual loss of the product. In addition, such conditions are often accompanied by severe environmental consequences, property damage, and occasionally loss of life. Consideration of these factors has caused a substantial upsurge in the construction costs and cost of maintenance for pipelines, even to the point to delaying the building of vital energy-carrying lines.
The maintenance of a pipeline is best effected by the continuous monitoring of the pipeline condition, beginning immediately after installation and continuing to seepage leaks and major blowouts. Leaks or blowouts on land are relatively easy to discover, for example, by ground of air survey, with sufficent time to get repair crews to the site and contain any product spill and repair the line. However, underground and underwater pipelines are not readily monitored by such survey techniques. As a result, massive catastrophic blowouts may occur which may not be immediately detected, resulting in great damage to property and the environment. For example, a crude oil pipeline rupture may cause a spill which drifts for many miles before the leak is detected. Furthermore, the correction of such a rupture on an emergency basis requires extremely sophisticated and expensive seabottom mobile equipment, divers and support ships.
In order to aid in the maintenance of lines, there are many prior art devices which are adapted to internally scan pipelines by use of a so-called "pig" device which is periodically inserted through difficult-to-monitor stretches of the pipeline and transported under power of the fluid flow in the pipeline. The prior art pigs include sensors suitable for detecting certain classes of corrosion and leaks in the pipeline. However, the prior art system devices are generally extremely limited in many areas, for example, the precision and resolution of the fault detection. In addition, the method for logging the sensed parameters as the pig is transported through the pipeline provides relatively poor location capability for any detected faults. Furthermore, the prior art systems are generally provided with on-board battery systems for powering the sensing and data recording networks, resulting in a relatively large and bulky pig. For example, the prior art pigs may be on the order of two to three thousand pounds in weight and up to forty-eight inches in length.
In addition, the present pig insertion systems for pipelines include manual "lubricators" which require operator intervention to operate a lock configuration which injects a pig into the flow of a line.
Accordingly, it is an object of the present invention to provide a high resolution, high sensitivity pipeline condition monitoring device.
It is another object to provide a relatively compact and lightweight pipeline condition monitoring system.
It is still a further object to provide an automatic pig insertion means for use in conjunction with a pipeline to be monitored.